1. Field of the Invention
The present invention is in the field of catalytic hydroprocessing of heavy hydrocarbon oils, particularly liquid petroleum residua and shale oils. More particularly, it concerns an improvement in catalytic hydrodesulfurization and hydrocracking of such heavy oils.
2. The Prior Art
The atmospheric or vacuum distillation of crude petroleum produces a residuum (bottoms) that contains sulfur and a substantial proportion of asphaltenes and other hydrocarbons boiling above 600.degree. C. Similarly, shale oil contains substantial fractions of these materials. In times past, these heavy fractions could economically find application in paving materials and the like. Today, however, the cost of petroleum demands that these materials be processed to form more valuable relatively low sulfur-relatively lower boiling hydrocarbon materials which can be used as fuels. It is known in the art that this reduction in sulfur and conversion to lower boiling hydrocarbons can be effected by contacting the residiuum or shale oil with hydrogen and a solid catalyst at elevated temperatures. Representative patents to such processes include U.S. Pat. No. 3,558,474 of Gleim, et al, and U.S. Pat. No. 3,841,996 of Jacobsen.
It will be appreciated that is is economically attractive to maximize the balance of catalyst life and activity to minimize heat imputs and catalyst replacement. It further will be appreciated that these heavy hydrocarbon feedstocks, by their very nature as bottoms fractions, contain substantial amounts of catalyst deactivators. It is a fundamental object of this invention to improve the stability of the catalysts used in hydroprocessing of these heavy petroleum feedstocks and thereby increase the useful life of these catalysts and improve the economics of heavy petroleum hydoprocessing. This object is accomplished herein by adding a fluoro component to the hydroprocessing feedstocks. Patents relating generally to petroleum processing in the presence of halogens or halogen compounds include:
U.S. Pat. No. 2,221,952 of Pier et al
U.S. Pat. No. 2,344,789 of Schmerling
U.S. Pat. No. 2,357,495 of Block
U.S. Pat. No. 2,953,516 of Gardner
U.S. Pat. No. 3,088,908 of Hansford
U.S. Pat. No. 3,305,477 of Peck et al
U.S. Pat. No. 3,717,586 of Suggitt et al.